    [dag_unify.core :refer (copy dissoc-paths fail? get-in ref? strip-refs unify)]))
 
 ;; TODO: convert all morphology rules to this format used for prepositions:
-(def preposition-plus-article
+(defonce preposition-plus-article
   [["a il"   "al"]
    ["a lo"   "allo"]
    ["a la"   "alla"]

                lexeme))
        (get lexicon surface-form))))

(def exceptions-rules
  (concat verbs/exceptions-rules
          adjectives/exceptions-rules
          nouns/exceptions-rules))

   true
   ""))

(defonce ppa-tokens-to-surface
  (map (fn [pair]
         [(re-pattern
           (str "\\b" (first pair) "\\b"))
          (second pair)])
       preposition-plus-article))

(defonce ppa-surface-to-tokens
  (map (fn [pair]
         [(re-pattern
           (str "\\b" (second pair) "\\b"))
